A freeze-fracture survey of the prostate gland is conducted for the first time. Our objectives include: 1) The preparation of a description of cells in the prostate gland, 2) their changes under different conditions of fixation, 3) the observation of membrane events related to secretory processes and 4) the elucidation of temperature and fixation related structural alteration of the membranes of the endoplasmic reticulum and nuclear envelope.